The present invention generally relates to information signal track search systems in rotary recording medium reproducing apparatuses, and more particularly to a system capable of quickly searching for a desired information signal track position on a rotary recording medium which is to be reproduced.
Rotary recording medium reproducing apparatuses of the so-called electrostatic capacitance system are being reduced to practical use. In such an apparatus, a recorded information signal is reproduced from a rotary recording medium (hereinafter simply referred to as a disc) which is recorded with an information signal such as a video signal and an audio signal as variations in geometrical configuration, according to variations in electrostatic capacitance between the disc and an electrode of a reproducing stylus which reproduces the disc.
The above disc is recorded with a main information signal such as the video signal and the audio signal, and reference signals for tracking control. The reference signals are recorded on the disc so that the reproducing stylus correctly scans over the main information signal track.
Guide grooves for guiding the reproducing stylus are not formed in the above disc. Hence, it is possible to forcibly move the reproducing stylus along the radial direction of the disc in a state where the reproducing stylus makes sliding contact with the surface of the disc. Accordingly, besides the usual normal reproduction, it is possible to carry out various special reproduction or the so-called trick-play such as still-picture reproduction, slow-motion reproduction, high-speed reproduction, and high-speed position search. The high-speed position search in particular is carried out by moving a reproducing transducer provided with the reproducing stylus to a position in the vicinity of the desired track position on the disc from a resting position, at a super-high speed in the range of 2000 times the moving speed upon normal reproduction (2000-times-speed), for example. Thereafter, the search is completed by moving the reproducing transducer to the desired track position at a high-speed in the range of 64 times the moving speed upon normal reproduction (64-times-speed), for example. The numerical value of the multiple speed (times-speed) indicates the moved quantity of the reproducing stylus with respect to the tracks for one revolution of the disc.
The reproducing stylus of the reproducing transducer is provided at the tip end of a cantilever. The rear end part of this cantilever is supported by a resilient support member. Thus, during the above super-high-speed search, the tip end of the reproducing stylus assumes a position lagging the fulcrum of the cantilever along the moving direction, due to the friction between the reproducing stylus and the disc. As a result, the cantilever becomes inclined by a certain angle along the moving direction.
Conventionally, when searching for a desired track, the super-high-speed movement of the reproducing transducer is stopped at the point in time when an address preceding that of the desired track is reproduced, and thereafter, the reproducing transducer was moved to the desired track at a high-speed which is slower than the super-high-speed.
However, at the point in time when the above super-high-speed movement of the reproducing transducer is stopped, the direction along which a compensation damping force (restoration force) of the resilient support member is applied to the cantilever, is the same as the direction of the high-speed search movement to the desired track. Hence, in the above conventional system, the above compensation damping force and the search movement force are added, and an overrun in which the reproducing stylus moves past the desired track is easily introduced due to the added force. Therefore, it becomes necessary to carry out a high-speed search in order to return the reproducing stylus by a quantity corresponding to the overrun quantity. Thus, there was a disadvantage in that additional time was required to search for the desired track because of the above high-speed search necessary to return the reproducing stylus.